Analog-to-digital converters (ADCs) are used in a variety of devices in which it is desirable to convert an analog signal to a digital signal. For example, ADCs may be found in a various communication devices such as radios, cell phones, modems, etc. ADCs may also be found in computer components, such as sound cards, network cards, I/O devices, etc. ADCs may also be used in a variety of other applications.
One type of ADC, the delta-sigma ADC (also called a sigma-delta ADC) is widely used. Delta-sigma ADCs quantize an analog input signal to be converted by displacing the quantization noise to a frequency-band spaced away from the band of the signal, such that the noise can be easily filtered out by a filter operating in the digital domain. This results in improvement of the signal-to-noise (SNR) of the digital signal.